Quick approach for FS160 wheels
Introduction
This page shows the results of an experiment to speed up the conversion of N wheels. It is similar to my proven method of making a new rim on an existing N wheel as described a few years back. The main drawback in producing wheels is the time it takes to turn a new rim or an entire tyre. If it takes 8 hours to produce a full wheelset for a loco then rewheeling a loco is not undertaken easily. However if we can obtain the tyres sec we will make a large step forward. Instead of the major part of an hour per wheel we will then be left with only several minutes shaving and cutting. As it happens certain continental wheels have a diameter that would fit a 2mm size tyre. Thus an experiment with the leftovers from a P8 that has 11 mm wheels (1750mm to be exact) was tried with 11mm rims from the 2mm Scale Association. This page shows how I did proceed.
conversion in steps
The first step was in making a small tool for holding the wheel during turning. It is a piece of steel with a plastic insert with a tight hole that holds the 1.5 mm axle. The diameter of the tool is such that a wheel rim fits over it. That is because the 2mm tyre have a small inner rim at front about .2mm thick. Thus they will fit only from the front but in order to cut of the back of the N wheel you end up with something like the tool on the photo. The next step is fitting the wheel into the tool by pressing the axle with the headstock into the plastic center. I use a cutting tool with sharp corners to be able to produce the cut out for the rim, but if you like to change your toolbits often then go ahead and use roundnose tools. We can now shave off the rim.
Bring it up to diameter of 10.5 mm and note down the setting of your lathe for the next wheel.
Create the space for the inner rim of the tyre at the front. Note that in this enlargement you can clearly see grooves on the new 2mm tyre those need to be polished away.
Test fit the tyre, if you find a small burr use a fine file to remove it.
If it is in line with the front of the wheel center you have the original width of the N wheel again.
Now fix it with glue, for good fits this no longer available Loctite 601 is ideal, use a wire on an old brush handle for dispensing a small droplet. There exist replacement products with different numbers but identical purpose.
Be a bit careful with removing the remains of the old tyre that is still sticking out. Too much strain and the wheel will fall apart.
Cut through the spokes first with a reversed cutting blade, otherwise your spokes may be damaged of will bend due to too much strain.
When that is done then you can use a coarser tool to finish the center.
Now this is a voluntary stage to produce a better FS160 tyre profile, less acute angles and smooth!. The 2mm rims have a high surface roughness and need polishing and also some fine tuning of the flange is necessary to arrive at better way finding properties. However too much pressure while polishing heats up the tyre. If it becomes warm it will expand and the whole tyre will separate from the plastic center. The wheel is not worthwhile to recover after that happens. I use a stick with 600 and 1200 waterproof finishing paper glued to it, you see the 600 on top. This fine paper is readily available in car utility shops. It would of course be much better to polish the rims first off stage before mounting.
Now pull the wheel out and remove it from the axle.
This is how they look, top and bottom, there are burrs on the back of the spokes primarily this depends on how careful you work.
The spokes can be cleaned with a sharp scalpel. Here a five pack of wheels. The top left one was damaged by too much heat during polishing and has excess wobble. The second left on top shows what happens if you don't cut the spokes first with a cutting blade, they are a bit curvy and no longer in line, but I am sure you won't see that when it runs.
conclusion
Apart from buying entire FS160 wheels this looks the right way forward for conversion of German R-T-R stock. It indeed takes only between 5-10 minutes to produce a raw wheel. Finishing the wheels by scraping the burrs from spokes at the back is a bit of nuisance, but doubtless that can be helped with some filler or trying a different procedure for this stage.
copyright: Henk Oversloot
date: 20 may 2003
